The macrophage is a mediator of chronic inflammatory changes in metabolic disorders, such as diabetes, serving as a link between obesity, inflammation, and metabolic signaling at the site of the adipose tissue. The proposed project will focus on understanding the function of macrophages in metabolic disease pathology by specifically focusing on the function of Cbl-associated protein (CAP) in macrophages. The goal of the proposal is to expand observations of mice with a bone marrow-specific deletion of the CAP gene (CAPKO) protected from high fat diet-induced diabetes. While previous experiments have determined the importance of CAP in macrophage migration in vitro, these studies will focus on the role of CAP in macrophage migration, maturation, and activation in bone marrow-derived macrophages from CAPKO and littermate control mice. To achieve this, Aim 1will build on preliminary results to establish bone marrow- derived macrophages (BMDMs) as a relevant model to study CAP action in macrophages and CAP- dependent signaling. Our lab has demonstrated a critical role for CAP in focal adhesion structures in fibroblasts;therefore, Aim 2 will evaluate the function of CAP in macrophage maturation and migration in relation to adipose tissue. Since macrophage migration and activation involve phosphorylation events, Aim 3 will investigate signal transduction changes in both actin adhesion pathways and insulin-related signaling pathways. Aim 4 will evaluate altered macrophage activation as a potential mechanism for diminished macrophage recruitment to adipose tissue in CAPKO mice. Studies will investigate important profiles of cytokine gene and protein expression in BMDMs from both CAPKO and control mice. This study is the first in-depth examination of the role of CAP in macrophage utilizing an ex vivo model. A better understanding of CAP action in macrophages will enable a comprehensive view of diabetes disease progression and ultimately potential treatment options. PUBLIC HEALTH RELEVANCE: One of the major risk factors for diabetes is obesity which is quickly becoming an epidemic in both industrialized and developing nations. This research will enhance our understanding of metabolic signaling in the disease progression from obesity to diabetes by examining macrophage action and ultimately provide insights into a potential target for new therapies in disease treatment.